The etiology of the functional psychoses such as schizophrenia and mood disorder is not clear. It is assumed that there is the disturbed integration of function in both hemispheres in the functional psychoses. We have tried this research for the purpose to clear the etiology of the functional psychoses by using the neuropsychological, neurophysiological, and neuroimaging methods.Yamaguchi and Kurachi studied the relationship between frontal blood flow and clinical findings in schizophrenic patients. Compared with the normal controls, the patients showed a reduced relative frontal flow in the left hemisphere. Sato and Kojima investigated the eye fixations and movements during maze test in schizophrenia. Yamauchi investigated an asymmetry of EEG background activity in schizophrenia. Niwa and Machiyama studied the auditory event-related potentials in schizophrenia. Takahashii investigated the CNV in depression. Hozaki and Torn performed neuropsychological investigations on chronic schizophrenia from aspects of its frontal function.